JP3213862B2 - Transfer-type inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus. More specifically, the present invention relates to a transfer-type ink jet recording apparatus that forms an ink image on a transfer medium and then transfers the image to a recording medium to obtain an ink image on the recording medium.

[0002]

2. Description of the Related Art A transfer-type ink jet recording apparatus has high reliability without ink jet clogging due to unintended contact between recording paper or paper dust and a recording head, and provides high quality printing without ink bleeding. Is obtained. As such a transfer type ink jet printer, configurations described in US Pat. No. 4,538,156 and US Pat. No. 5,099,256 are known.

In these apparatuses, an ink jet recording head having a plurality of nozzles (hereinafter, referred to as a recording head) is provided between a cylindrical ink image holding medium and a gap via a gap.
Is provided. In the apparatus disclosed in U.S. Pat. No. 4,538,156, the nozzles of the recording head are arranged in the axial direction of the ink image holding medium. The ink image recording on the recording paper is performed by a process of writing the ink image on the ink image holding medium and a transfer process of transferring the ink image onto the recording paper. In the ink image writing step, the recording head forms an ink image on the cylinder while moving by a fixed amount per rotation in the axial direction of the ink image holding medium in synchronization with the rotation of the cylindrical ink image holding medium. The previous recording area is scanned by a plurality of rotations of the ink image holding medium. In both devices, in the transfer step, the recording paper, which is the recording medium, is brought into contact with the ink image holding medium and pressed from behind to transfer the ink image onto the recording paper. Thereafter, the recording paper is peeled from the ink image holding medium and discharged.

[0004] In this manner, the ink image is formed on a cylindrical ink image holding medium made of a material such as silicone rubber or the like in which ink bleeding is small and the attached ink is easily peeled off.
When this ink image is transferred to recording paper after being in a semi-dry state, printing can be performed on the recording paper without causing ink bleeding.

[0005]

On the other hand, however, the ink is in a semi-dry state at the time of transfer,
Adhesion of the ink to the recording paper is reduced, and particularly in a pattern formed by continuous dots such as a line segment, a part of the ink image is likely to be untransferred, and the print quality may be degraded. .

In a printer of the type in which the image once formed on the image holding drum is transferred onto a recording sheet, it is proposed to provide a speed difference between the image holding drum and the recording sheet in order to increase the transfer efficiency. (Japanese Patent Laid-Open No. 4-70)
No. 785), the technology disclosed therein transfers an image held by electrostatic force to recording paper by electrostatic force, and is directly used in a printing method that does not use electrostatic force at the time of transfer such as an ink jet printer. Not available.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing problems, and has as its object to provide a novel method that can reliably transfer ink on an ink image holding drum to recording paper regardless of the dryness of ink. It is an object of the present invention to provide a transfer type ink jet recording apparatus.

[0008]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides an ink jet recording head for ejecting ink droplets corresponding to data to be recorded, and an ink which receives the ink droplets and is elastically deformable. Image holding means, arranged to be able to advance and retreat in the transfer area of the ink image holding means, so as to cause a slip in a state where a nip pressure is applied to the ink image holding means,
It is characterized by comprising a pressing roller held at a predetermined angle with respect to the moving direction of the ink image holding means.

Further, the predetermined angle is 85-85 with respect to the moving direction of the ink image holding means in the axial center direction of the pressing roller.
It is characterized by being in the range of 95 degrees.

[0010]

[0011]

[0012]

According to the above method, the pressing roller presses the ink holding belt at a predetermined rotational speed difference or at a predetermined skew angle. Thus, a small and inexpensive transfer device can be realized with a simple mechanism.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording apparatus of the present invention will be described in detail below with reference to embodiments.

FIG. 1 is a perspective view of the ink jet printer of the first embodiment. An ink jet recording head 2 and a pressing roller 3 as a transfer unit are arranged around an ink image holding drum 1 as an ink image holding medium.

The recording head 2 is a line type ink jet recording head using a piezoelectric element, and has a plurality of nozzles at regular intervals in the axial direction of the ink image holding drum 1. In the case of the present embodiment, the recording head 2 has 512 nozzles at a pitch of 16/600 inch, and the head moving device 21 moves the recording head 2 in the axial direction of the ink image holding drum 1.
The head is moved by 1/600 inch per rotation of the ink image holding drum 1, and an image for one page of the ink image holding drum is formed by 16 rotations.

Each of the nozzle openings communicates with a pressure chamber for receiving ink from an ink tank, similarly to a normal serial printer, and includes a piezoelectric element, a heating element, and the like provided in these pressure chambers. Is operated by the print data to cause the ink in the pressure chamber to fly from the nozzle opening.

The ink image holding drum 1 is rotatably supported by a frame (not shown), and has an elastic layer made of silicone rubber laminated around a metal tube. The area is divided into two: an area 11 and a non-recording area 12 which is not shaded. In the case of this embodiment, 8
An ink image holding drum 1 having a diameter of 0 mm is used. In addition, the elastic layer is desirably a rubber material that easily peels off the ink image,
In addition to silicone rubber, fluorosilicone rubber, fluorine rubber and the like can be used.

The pressing roller 3 has on its surface a friction layer made of a material having a larger friction coefficient to the recording paper than the friction coefficient of the recording paper 4 to the ink image holding drum 1, for example, rubber or ceramic sprayed. It is pivotally supported by a pressing lever 32 having the fixed support shaft 31 as a swing axis. The pressing roller 3 is rotatably driven by an opening / closing motor 35, and reciprocates in the direction of arrow C in the figure by rotation of a pressing opening / closing shaft 34 rotatably supported by a frame (not shown) and having an eccentric cam. Then, it is configured to be able to press and release the press. The transfer pressure is generated by the transfer pressure applying means 33, and is controlled within the range of 5 to 50 kg weight in this embodiment.

The ink image holding drum 1 includes a drum gear 5
3, connected to the pulse motor 5 via the drum-side intermediate gear 52 and the motor gear 51, and driven to rotate in the direction of arrow A in the figure. The pressing roller 3 is connected to the drum-side intermediate gear 52 via a roller gear 55 and a roller-side intermediate gear 54, and determines a speed difference ΔV so that the pressing roller 3 slips with the surface peripheral speed V1 of the ink image holding drum 1. With the speed V2
It is configured to be driven to rotate in the direction of arrow B in the figure.

The outer diameter of the ink image holding drum 1 is D1, the outer diameter of the pressing roller 3 is D2, and the number of teeth of the drum gear 53 is Z5.
3. Assuming that the number of teeth of the roller gear 55 is Z55, the transmission ratio of the transmission mechanism is expressed by the following equation.

(D1 / D2) ≠ (Z53 / Z55) In addition to the gear mechanism of the present embodiment, a toothed belt mechanism or a pulley mechanism can be used as the transmission mechanism.

The drum origin detection plate 13 is fixed to the ink image holding drum 1, and when the ink image holding drum 1 rotates and the head of the recording area 11 reaches the recording head 2, an origin signal is output from the origin detector 14. The generated print data is output to the recording head 2 to cause ink droplets to fly, thereby forming an ink image on the ink image holding drum 1.

Next, the operation of the apparatus configured as described above will be described with reference to FIG.

In a state where the pressing roller 3 is separated from the ink image holding drum 1 (FIG. 2A), the ink image holding drum 1 is rotated at a steady speed V1, an origin signal is generated, and the writing start position is determined by the recording head. 2, print data from a host or the like is output to the recording head 2. The ink droplets ejected from the recording head 2 sequentially form ink images corresponding to the print data on the surface of the ink image holding drum 1.

When an ink image is formed while the ink image holding drum 1 is rotated as described above, the ink image is in a semi-dry state due to the evaporation of the solvent constituting the ink.
A predetermined amount, for example, one page of the ink image is transferred to the ink holding drum 1
In this stage, the recording paper 4 is fed by the paper feeder 37 in the direction of arrow D in the drawing and supplied to the transfer area in accordance with the timing at which the writing start position of the ink image holding drum 1 moves to the transfer area. When the leading end of the recording paper 4 reaches the printing area, the pressing opening / closing shaft 34 is rotated, and the pressing roller 3 is moved by the transfer pressure applying means 33 in the direction of the arrow E in FIG. Press with the nip pressure.

As a result, the recording paper 4 is sandwiched between the ink image holding drum 1 and the pressing roller 3, and is pressed against the ink pattern image with a constant force by the pressing force from the pressing roller 3 (FIG. 2 (b)). )) Thereafter, the ink image on the ink image holding drum 1 is transferred onto the recording paper 4 while maintaining this state.

In this process, since the pressing roller 3 has a greater frictional resistance to the recording sheet 4 than the ink image holding drum 1, the recording sheet 4 moves at a speed V 2 which is as close as possible to the peripheral speed V 2 of the pressing roller 3. I do. As a result, the recording paper 4 has a speed difference ΔV = | V1−V2 | with respect to the peripheral speed V1 of the ink image holding drum 1, and the ink image has a difference between the ink holding drum 1 and the recording paper 4. The ink image is made of a rubber material that easily separates from the ink image and the surface of the ink holding drum 1 due to a shearing force that tends to slip, and the ink image is easily adhered to the recording paper 4. And is transferred to the recording paper 4 with high efficiency.

When the transfer of one page is completed in this way, the pressing opening / closing shaft 34 rotates, the pressing roller 3 is separated from the ink image holding drum 1 to release the pressing, and the printing of one page is completed. .

According to this embodiment, a constant speed difference can always be obtained even if a load variation such as pressing force occurs due to the transmission ratio of the transmission mechanism, and a small and inexpensive transfer device can be realized with a simple mechanism. It becomes possible.

In this embodiment, the case where a line type recording head is used has been described as an example. However, it is apparent that the same operation can be obtained by using a serial type recording head.

FIG. 3 shows a second embodiment. The apparatus of the present embodiment shows an embodiment in which the ink holding means is constituted by an endless belt. Reference numeral 6 in the drawing denotes an ink image holding means constituted by an endless belt, which is a thin plate base made of spring steel or the like. The above-mentioned elastic material such as silicon rubber is adhered to the surface of the substrate.

The length of the recording area of the ink image holding belt 6 is at least as long as one page of the recording paper 4, and each end is connected to an unwinding pulley 61 and a winding pulley 62. The unwinding pulley 61 and the take-up pulley 62 are in contact with the outer periphery of the feed drum 65. During standby, the leading end of the recording area 11 stops at a position facing the recording head 7, and the unwinding pulley 61 side It is in a state where tension is applied so that there is no slack when it is wound around.

The ink image holding belt 6 includes a feed drum 65
The nip pressure is applied by a pinch roller pressing means (not shown), and the nip is moved by a frictional force with the feed drum 65. Feed drum 65
Is rotated in the direction of arrow F in FIG.
The ink holding belt 6 moves in the direction of arrow G in the figure (hereinafter, referred to as the main scanning direction), the recording area is unwound from the unwinding pulley 61, and at the same time, the winding motor 64 is moved so that the ink holding belt 6 is not loosened. Is pulled and wound on the take-up pulley 62 driven by.

The recording head 7 is a serial type ink jet recording head using a piezoelectric element, and has a plurality of nozzles at regular intervals in the main scanning direction of the ink image holding belt 6. In the case of the present embodiment, the recording head 7 is moved at a pitch of 1/600 inch in the moving direction of the ink image holding belt 6.
It has a plurality of nozzles, is installed with a predetermined gap from the ink holding belt 6, and is moved by a head moving device 71 in a direction perpendicular to the main scanning direction of the ink image holding belt 6 (hereinafter referred to as a sub-scanning direction). ).

Each of these nozzles is configured to fly ink from a nozzle opening, similarly to the recording head 2 of the first embodiment.

The feed drum 65 is connected to the pulse motor 5 via a drum gear 53, a drum-side intermediate gear 52, and a motor gear 51, and is driven to rotate in the direction of arrow F. The pressing roller 3 is connected to the drum-side intermediate gear 52 via a roller gear 55 and a roller-side intermediate gear 54, and has a speed difference ΔV so that the pressing roller 3 slips with the surface peripheral speed V1 of the ink image holding belt 6. It is configured to rotate in the direction of arrow H at the speed V2. In addition to the gear mechanism of the present embodiment, a toothed belt mechanism, a pulley mechanism, or the like can be used as the transmission mechanism.

The surface peripheral speed of the ink image holding belt 6 is V
1. If the peripheral speed of the pressing roller 3 is V2, the number of teeth of the drum gear 53 is Z53, and the number of teeth of the roller gear 55 is Z55,
The transmission ratio of the transmission mechanism is expressed by the following equation.

(V1 / V2) ≠ (Z53 / Z55) Next, the operation of the apparatus configured as described above will be described with reference to FIG.

During standby, the head of the recording area of the ink holding belt 6 stops at the position facing the recording head 7 as described above, and the pressing roller 3 is separated from the ink holding belt 6.

When a print start command is issued, the recording head 7
Starts the forward movement in the sub-scanning direction by the head driving device 71, and at the same time, print data according to the print head position at the time of forward movement is output from the host or the like to the print head 7, and the ink image 1
The writing of the line starts. When the forward movement of the recording head 7 ends, the writing of the first line of the ink image ends, and the ink holding belt 6
The print head 7 is fed by the pitch (64/600 inches) and stopped, and the print head 7 starts to move backward in the sub-scanning direction by the head driving device 71. The data is output to the recording head 7 and the second line is written. At the time when the recording head 7 has completed the backward movement, the writing of the second line of the ink image has been completed, and the ink holding belt 6 is fed by the feed drum 65 by one pitch (64/600 inches). Thereafter, the recording head 7 reciprocates until a predetermined amount of print data is completed, and the ink holding belt 6 is intermittently fed to form an ink image on the ink holding belt 6.

As described above, when the ink image is formed while the ink image holding belt 6 is intermittently moved, the ink image becomes a semi-dry state due to the evaporation of the solvent constituting the ink.

The recording paper 4 is fed by the paper feeder 37 in the direction of arrow D in the figure and supplied to the transfer area at the timing when the write start position of the ink image holding belt 6 moves to the transfer area. When the leading end of the recording paper 4 reaches the printing area, the pressing opening / closing shaft 34 rotates, and the pressing roller 3 is moved by the transfer pressure applying means 33 in the direction of arrow E in the drawing to apply a predetermined nip pressure to the ink image holding belt 6. Press on.

Thus, the recording paper 4 is sandwiched between the ink image holding belt 6, the feed roller 65, and the pressing roller 3,
The ink pattern image is pressed against the ink pattern image with a constant force by the pressing force from the pressing roller 3. Thereafter, the ink image on the ink image holding belt 6 is transferred onto the recording paper 4 while maintaining this state.

In this process, as described above, since the pressing roller 3 has a greater frictional resistance to the recording sheet 4 than the ink image holding belt 6, the recording sheet 4 matches the peripheral speed V2 of the pressing roller 3 as much as possible. It moves at the speed V2. As a result, the recording paper 4 has a peripheral speed V of the ink image holding belt 6.
1 has a speed difference ΔV = | V1−V2 |, and a shearing force is generated between the ink holding belt 6 and the recording paper 4 in the ink image, so that the ink image and the ink holding belt 6 is made of a rubber material that is easy to peel off, and the ink image is easily adhered to the recording paper 4. Therefore, the ink image is peeled from the surface of the ink image holding belt 6 and transferred to the recording paper 4 with high efficiency. .

When the transfer of one page has been completed in this way, the pressing / opening shaft 34 rotates to separate the pressing roller 3 from the ink image holding belt 6 and release the pressing. Is moved in the direction opposite to the main scanning direction, and is simultaneously taken up by the unwinding pulley 61 driven by the unwinding motor 63, and stopped at the position where the recording head position of the ink holding belt 6 faces the recording head 7, The printing operation ends.

According to this embodiment, a constant speed difference is always obtained even if a load variation such as pressing force occurs due to the transmission ratio of the transmission mechanism, and a small and inexpensive transfer device can be realized with a simple mechanism. . In addition, it is possible to increase the distance between the recording area and the transfer area, and to extend the time from the formation of the ink pattern to the transfer so that the ink image can be sufficiently dried. It is easy to dispose a cleaning unit for removing the ink image remaining in the ink, and a heater and a blowing unit for volatilizing the solvent of the ink having a low drying rate.

FIG. 5 shows a third embodiment. The apparatus according to the present embodiment is an embodiment in which a pressing roller is held at a set angle with respect to the moving direction of the ink holding means, and the ink image holding drum 1 as an ink image holding medium is used.
The ink jet recording head 2 and a skew pressing roller 8 as a transfer unit are arranged around the printer.

FIG. 6 is a front view of the roller section viewed from the direction of arrow J in the drawing, which is the direction in which the recording paper 4 is fed. The center lines of the ink holding drum 1 and the skew pressing roller 8 are parallel. 7, in the plan view seen from the vertical upper direction of the arrow J direction in the figure, the axis center lines of the ink holding drum 1 and the skew pressing roller 8 intersect at the skew angle θ with the axial center point as an intersection. The configuration is as follows.

The ink image holding drum 1 has a drum gear 53,
It is connected to the pulse motor 5 via the motor gear 51 and is driven to rotate in the direction of arrow A in the figure.

Next, the operation of the thus configured apparatus will be described.

When the skew pressing roller 8 is separated from the ink image holding drum 1, the ink image holding drum 1 is rotated at a steady speed V 1, and when the origin signal is generated and the writing start position is opposed to the recording head 2, the ink is stopped. Print data from a host or the like is output to the recording head 2 so that the ink image 15 on the surface of the holding drum 1 is formed obliquely at a skew angle θ with respect to the axial direction as shown in FIG. The ink droplets ejected from the recording head 2 sequentially form ink images corresponding to the print data on the surface of the ink image holding drum 1.

When a predetermined amount of data is thus recorded on the ink image holding drum 1, the recording paper 4 is supplied from a paper feeding device (not shown) in a direction perpendicular to the axial direction of the skew pressing roller 8. When the leading end of the recording paper 4 reaches the printing area, the skew pressing roller 8 is moved toward the ink image holding roller 1 to press the recording paper 4 against the ink pattern image. Thereafter, the ink image on the ink image holding drum 1 is transferred onto the recording paper 4 while maintaining this state.

In this process, the skew pressing roller 8
The recording paper moves in a direction perpendicular to the axial direction of the skew pressing roller 8 because the frictional resistance against the recording paper 4 is larger than that of the ink image holding drum 1. As a result, the recording paper 4 is skewed at a skew angle θ with respect to the direction perpendicular to the axis of the ink image holding drum 1, and the surface of the ink image holding drum 1 and the recording paper 4 slip within the nip width. The slip amount can be represented by (nip width) × tan (skew angle θ). The ink image is made of a rubber material that easily causes a shearing force between the ink holding drum 1 and the recording paper 4 so as to slip between the ink holding drum 1 and the recording paper 4. Since the ink image is easily adhered to the paper 4, the ink image is separated from the surface of the ink image holding drum 1 and is transferred to the recording paper 4 with high efficiency.

When the transfer of one page has been completed in this way, the skew pressing roller 8 is separated from the ink image holding drum 1 and the pressing is released to complete the printing of one page.

The skew angle θ is equal to or less than 5 degrees (the angle in the direction of the axis of the pressing roller with respect to the moving direction of the ink image holding medium is 85 to 95 degrees). A state occurs in which the ink is not pressed because it comes off the ink holding drum 1. Preferably, the skew pressing roller 8 is at most 3 degrees (the angle of the axial direction of the pressing roller with respect to the moving direction of the ink image holding medium is 87 to 93 degrees).
And the amount of slippage of the ink image holding drum 1 is relatively small, and a high-quality transfer image with almost no displacement of the ink image during transfer can be obtained.

According to this embodiment, since the pressing roller presses at a predetermined skew angle, a constant slip ratio can always be obtained even if a load variation such as pressing force occurs, and a simple mechanism that is small and inexpensive. It is possible to realize a transfer device.

In this embodiment, the case where a line recording head is used has been described as an example. However, it is apparent that the same operation can be obtained by using a serial recording head.

[0058]

As described above, in the present invention,
An ink jet recording head for ejecting ink droplets in accordance with data to be recorded, an ink image holding means for receiving and elastically deforming the ink droplets, and an ink image holding means arranged to be able to advance and retreat to a transfer area of the ink image holding means; Since the pressure roller is provided with a rotation speed difference or a skew angle set so as to cause slippage in a state where a nip pressure is applied to the ink image, the ink image which has become semi-dry on the surface of the ink image holding means is subjected to shearing. The ink image can be reliably transferred to the recording medium by applying the peeling force by the force, and the print quality can be improved and the cleaning interval of the ink image holding means can be extended by a simple mechanism. A high quality transfer device can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet printer according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the ink jet printer according to the first embodiment of the present invention.

FIG. 3 is a perspective view of an ink jet printer showing a second embodiment of the present invention.

FIG. 4 is a view for explaining the operation of an ink jet printer according to a second embodiment of the present invention.

FIG. 5 is a perspective view of an ink jet printer showing a third embodiment of the present invention.

FIG. 6 is a front view illustrating the configuration of an inkjet printer according to a third embodiment of the invention.

FIG. 7 is a plan view illustrating the configuration of an inkjet printer according to a third embodiment of the invention.

[Explanation of Signs] 1: Ink holding drum (ink holding medium) 2: recording head (line type) 3: press roller (transfer means) 4: recording paper (recording medium) 5: pulse motor 6: ink holding belt 7: Recording head (serial type) 8: Skew pressing roller 11: Recording area 12: Non-recording area 13: Drum origin detecting plate 14: Origin detector 15: Ink image 21: Head moving device 31: Support shaft 32: Press lever 33: Transfer pressure applying means 34: Pressing opening / closing shaft 35: Opening / closing motor 51: Motor gear 52: Drum side intermediate gear 53: Drum gear 54: Roller side intermediate gear 55: Roller gear 65: Feed drum 66: Pinch roller

Claims (2)

(57) [Claims] An ink jet recording head for ejecting ink droplets corresponding to data to be recorded;
An ink image holding means that is elastically deformable, and a movement of the ink image holding means that is disposed so as to be able to advance and retreat in a transfer area of the ink image holding means so that the ink image holding means slips when a nip pressure is applied to the ink image holding means. A transfer type ink jet recording apparatus comprising a pressing roller held at a predetermined angle with respect to a direction. 2. The method according to claim 1, wherein the predetermined angle is 85 to 95 in the direction of the axis of the pressing roller with respect to the moving direction of the ink image holding means.
2. The transfer type ink jet recording apparatus according to claim 1, wherein the temperature is in a range of degrees.